LM335 Temperature Sensor

The LM335 is a precision temperature sensor IC that provides an accurate and linear temperature-dependent voltage output. Here's some detailed information about the LM335 sensor:

Features:

1. Temperature Range:
   • Operating: -40°C to +100°C
   • Calibrated: 0°C to +100°C
   • Full Range: -55°C to +150°C
2. Output Voltage:
   • Linearly proportional to temperature: 10 mV/°C
3. Calibration:
   • Factory calibrated to provide a precise output voltage for a given temperature range.
4. Accuracy:
   • Typically ±1°C at +25°C, and ±2°C over the full -40°C to +100°C range.
5. Power Supply:
   • Typically operates from 2.4V to 30V DC.
6. Output Configuration:
   • Provides a linear output voltage that can be directly interfaced with analog-to-digital converters (ADCs), microcontrollers, or other measurement devices.
7. Low Impedance Output:
   • The output impedance is low, making it suitable for driving long cables without significant signal degradation.
8. Low Quiescent Current:
   • Consumes very low current, making it suitable for battery-operated applications.

Applications:
 

• Temperature Measurement: Used in various applications where precise temperature monitoring is required, such as environmental monitoring systems, industrial control systems, and automotive applications.
• Temperature Compensation: Often employed in circuits requiring temperature compensation, such as in analog circuits and sensor modules.
• Portable Devices: Due to its low power consumption and small form factor, it is suitable for integration into handheld and portable devices.

Example Circuit:
 

Here's a basic example of how you might connect an LM335 sensor to an Arduino for temperature measurement:

const int lm335Pin = A0;  // LM335 analog pin connected to Arduino analog input A0

void setup() {
  Serial.begin(9600);    // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(lm335Pin);  // Read analog input
  float voltage = sensorValue * (5.0 / 1023.0);  // Convert analog reading to voltage (assuming 5V Arduino)
  
  // Convert voltage to temperature using LM335 formula (10 mV/°C)
  float temperatureC = (voltage - 2.73) / 0.01;  // 2.73V is the LM335 sensor's output at 0°C, 0.01V/°C is the slope
  
  // Print temperature to serial monitor
  Serial.print("Temperature: ");
  Serial.print(temperatureC);
  Serial.println(" °C");
  
  delay(1000);  // Delay before next reading
}

Explanation:
 

• Connect the LM335 sensor's Vout pin to Arduino's analog input pin (A0 in this example).
• In the Arduino sketch, read the analog voltage from the sensor using analogRead() function.
• Convert the analog reading to voltage using the formula (sensorValue * (5.0 / 1023.0)), assuming a 5V Arduino.
• Use the LM335 formula (voltage - 2.73) / 0.01 to convert voltage to temperature in degrees Celsius.
• Print the temperature readings to the Serial Monitor.

This example demonstrates how to interface the LM335 sensor with Arduino for temperature measurement. Adjust the code as needed based on your specific setup and requirements.